Eridanus (the river) is the sixth largest of the 88 modern constellations. It was also one of Ptolemy's 48 constellations. At its southern end is the first magnitudestar Archernar (α Eri).
Another well-known star in Eridanus is Epsilon Eridani, which has been popular in science fiction because it is relatively close and relatively sun-like. It is now known to have at least one planet (see Extrasolar planet).